diff --git a/cmd/api/cmd_sdk.go b/cmd/api/cmd_sdk.go
index 1b834af..383d549 100644
--- a/cmd/api/cmd_sdk.go
+++ b/cmd/api/cmd_sdk.go
@@ -39,6 +39,12 @@ func addSDKCommand(parent *cli.Command) {
 		wsPath                  string
 		pprofEnabled            bool
 		expvarEnabled           bool
+		cacheEnabled            bool
+		cacheTTL                string
+		cacheMaxEntries         int
+		cacheMaxBytes           int
+		i18nDefaultLocale       string
+		i18nSupportedLocales    string
 		termsURL                string
 		contactName             string
 		contactURL              string
@@ -84,6 +90,12 @@ func addSDKCommand(parent *cli.Command) {
 				wsPath:                  wsPath,
 				pprofEnabled:            pprofEnabled,
 				expvarEnabled:           expvarEnabled,
+				cacheEnabled:            cacheEnabled,
+				cacheTTL:                cacheTTL,
+				cacheMaxEntries:         cacheMaxEntries,
+				cacheMaxBytes:           cacheMaxBytes,
+				i18nDefaultLocale:       i18nDefaultLocale,
+				i18nSupportedLocales:    i18nSupportedLocales,
 				termsURL:                termsURL,
 				contactName:             contactName,
 				contactURL:              contactURL,
@@ -146,6 +158,12 @@ func addSDKCommand(parent *cli.Command) {
 	cli.StringFlag(cmd, &wsPath, "ws-path", "", "", "WebSocket endpoint path in generated spec")
 	cli.BoolFlag(cmd, &pprofEnabled, "pprof", "", false, "Include pprof endpoints in generated spec")
 	cli.BoolFlag(cmd, &expvarEnabled, "expvar", "", false, "Include expvar endpoint in generated spec")
+	cli.BoolFlag(cmd, &cacheEnabled, "cache", "", false, "Include cache metadata in generated spec")
+	cli.StringFlag(cmd, &cacheTTL, "cache-ttl", "", "", "Cache TTL in generated spec")
+	cli.IntFlag(cmd, &cacheMaxEntries, "cache-max-entries", "", 0, "Cache max entries in generated spec")
+	cli.IntFlag(cmd, &cacheMaxBytes, "cache-max-bytes", "", 0, "Cache max bytes in generated spec")
+	cli.StringFlag(cmd, &i18nDefaultLocale, "i18n-default-locale", "", "", "Default locale in generated spec")
+	cli.StringFlag(cmd, &i18nSupportedLocales, "i18n-supported-locales", "", "", "Comma-separated supported locales in generated spec")
 	cli.StringFlag(cmd, &termsURL, "terms-of-service", "", "", "OpenAPI terms of service URL in generated spec")
 	cli.StringFlag(cmd, &contactName, "contact-name", "", "", "OpenAPI contact name in generated spec")
 	cli.StringFlag(cmd, &contactURL, "contact-url", "", "", "OpenAPI contact URL in generated spec")
@@ -173,6 +191,12 @@ func sdkSpecBuilder(cfg specBuilderConfig) (*goapi.SpecBuilder, error) {
 		wsPath:                  cfg.wsPath,
 		pprofEnabled:            cfg.pprofEnabled,
 		expvarEnabled:           cfg.expvarEnabled,
+		cacheEnabled:            cfg.cacheEnabled,
+		cacheTTL:                cfg.cacheTTL,
+		cacheMaxEntries:         cfg.cacheMaxEntries,
+		cacheMaxBytes:           cfg.cacheMaxBytes,
+		i18nDefaultLocale:       cfg.i18nDefaultLocale,
+		i18nSupportedLocales:    cfg.i18nSupportedLocales,
 		termsURL:                cfg.termsURL,
 		contactName:             cfg.contactName,
 		contactURL:              cfg.contactURL,
diff --git a/cmd/api/cmd_spec.go b/cmd/api/cmd_spec.go
index e39d615..985408e 100644
--- a/cmd/api/cmd_spec.go
+++ b/cmd/api/cmd_spec.go
@@ -28,6 +28,12 @@ func addSpecCommand(parent *cli.Command) {
 		wsPath                  string
 		pprofEnabled            bool
 		expvarEnabled           bool
+		cacheEnabled            bool
+		cacheTTL                string
+		cacheMaxEntries         int
+		cacheMaxBytes           int
+		i18nDefaultLocale       string
+		i18nSupportedLocales    string
 		termsURL                string
 		contactName             string
 		contactURL              string
@@ -54,6 +60,12 @@ func addSpecCommand(parent *cli.Command) {
 			wsPath:                  wsPath,
 			pprofEnabled:            pprofEnabled,
 			expvarEnabled:           expvarEnabled,
+			cacheEnabled:            cacheEnabled,
+			cacheTTL:                cacheTTL,
+			cacheMaxEntries:         cacheMaxEntries,
+			cacheMaxBytes:           cacheMaxBytes,
+			i18nDefaultLocale:       i18nDefaultLocale,
+			i18nSupportedLocales:    i18nSupportedLocales,
 			termsURL:                termsURL,
 			contactName:             contactName,
 			contactURL:              contactURL,
@@ -96,6 +108,12 @@ func addSpecCommand(parent *cli.Command) {
 	cli.StringFlag(cmd, &wsPath, "ws-path", "", "", "WebSocket endpoint path in generated spec")
 	cli.BoolFlag(cmd, &pprofEnabled, "pprof", "", false, "Include pprof endpoints in generated spec")
 	cli.BoolFlag(cmd, &expvarEnabled, "expvar", "", false, "Include expvar endpoint in generated spec")
+	cli.BoolFlag(cmd, &cacheEnabled, "cache", "", false, "Include cache metadata in generated spec")
+	cli.StringFlag(cmd, &cacheTTL, "cache-ttl", "", "", "Cache TTL in generated spec")
+	cli.IntFlag(cmd, &cacheMaxEntries, "cache-max-entries", "", 0, "Cache max entries in generated spec")
+	cli.IntFlag(cmd, &cacheMaxBytes, "cache-max-bytes", "", 0, "Cache max bytes in generated spec")
+	cli.StringFlag(cmd, &i18nDefaultLocale, "i18n-default-locale", "", "", "Default locale in generated spec")
+	cli.StringFlag(cmd, &i18nSupportedLocales, "i18n-supported-locales", "", "", "Comma-separated supported locales in generated spec")
 	cli.StringFlag(cmd, &termsURL, "terms-of-service", "", "", "OpenAPI terms of service URL in spec")
 	cli.StringFlag(cmd, &contactName, "contact-name", "", "", "OpenAPI contact name in spec")
 	cli.StringFlag(cmd, &contactURL, "contact-url", "", "", "OpenAPI contact URL in spec")
diff --git a/cmd/api/cmd_test.go b/cmd/api/cmd_test.go
index 4df3385..8fadd18 100644
--- a/cmd/api/cmd_test.go
+++ b/cmd/api/cmd_test.go
@@ -115,6 +115,24 @@ func TestAPISpecCmd_Good_JSON(t *testing.T) {
 	if specCmd.Flag("expvar") == nil {
 		t.Fatal("expected --expvar flag on spec command")
 	}
+	if specCmd.Flag("cache") == nil {
+		t.Fatal("expected --cache flag on spec command")
+	}
+	if specCmd.Flag("cache-ttl") == nil {
+		t.Fatal("expected --cache-ttl flag on spec command")
+	}
+	if specCmd.Flag("cache-max-entries") == nil {
+		t.Fatal("expected --cache-max-entries flag on spec command")
+	}
+	if specCmd.Flag("cache-max-bytes") == nil {
+		t.Fatal("expected --cache-max-bytes flag on spec command")
+	}
+	if specCmd.Flag("i18n-default-locale") == nil {
+		t.Fatal("expected --i18n-default-locale flag on spec command")
+	}
+	if specCmd.Flag("i18n-supported-locales") == nil {
+		t.Fatal("expected --i18n-supported-locales flag on spec command")
+	}
 	if specCmd.Flag("terms-of-service") == nil {
 		t.Fatal("expected --terms-of-service flag on spec command")
 	}
@@ -216,6 +234,61 @@ func TestAPISpecCmd_Good_SummaryPopulatesSpecInfo(t *testing.T) {
 	}
 }
 
+func TestAPISpecCmd_Good_CacheAndI18nFlagsPopulateSpec(t *testing.T) {
+	root := &cli.Command{Use: "root"}
+	AddAPICommands(root)
+
+	outputFile := t.TempDir() + "/spec.json"
+	root.SetArgs([]string{
+		"api", "spec",
+		"--cache",
+		"--cache-ttl", "5m0s",
+		"--cache-max-entries", "42",
+		"--cache-max-bytes", "8192",
+		"--i18n-default-locale", "en-GB",
+		"--i18n-supported-locales", "en-GB,fr,en-GB",
+		"--output", outputFile,
+	})
+	root.SetErr(new(bytes.Buffer))
+
+	if err := root.Execute(); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	data, err := os.ReadFile(outputFile)
+	if err != nil {
+		t.Fatalf("expected spec file to be written: %v", err)
+	}
+
+	var spec map[string]any
+	if err := json.Unmarshal(data, &spec); err != nil {
+		t.Fatalf("expected valid JSON spec, got error: %v", err)
+	}
+
+	if got := spec["x-cache-enabled"]; got != true {
+		t.Fatalf("expected x-cache-enabled=true, got %v", got)
+	}
+	if got := spec["x-cache-ttl"]; got != "5m0s" {
+		t.Fatalf("expected x-cache-ttl=5m0s, got %v", got)
+	}
+	if got := spec["x-cache-max-entries"]; got != float64(42) {
+		t.Fatalf("expected x-cache-max-entries=42, got %v", got)
+	}
+	if got := spec["x-cache-max-bytes"]; got != float64(8192) {
+		t.Fatalf("expected x-cache-max-bytes=8192, got %v", got)
+	}
+	if got := spec["x-i18n-default-locale"]; got != "en-GB" {
+		t.Fatalf("expected x-i18n-default-locale=en-GB, got %v", got)
+	}
+	locales, ok := spec["x-i18n-supported-locales"].([]any)
+	if !ok {
+		t.Fatalf("expected x-i18n-supported-locales array, got %T", spec["x-i18n-supported-locales"])
+	}
+	if len(locales) != 2 || locales[0] != "en-GB" || locales[1] != "fr" {
+		t.Fatalf("expected supported locales [en-GB fr], got %v", locales)
+	}
+}
+
 func TestAPISpecCmd_Good_GraphQLPlaygroundFlagPopulatesSpecPaths(t *testing.T) {
 	root := &cli.Command{Use: "root"}
 	AddAPICommands(root)
@@ -758,6 +831,24 @@ func TestAPISDKCmd_Good_ValidatesLanguage(t *testing.T) {
 	if sdkCmd.Flag("expvar") == nil {
 		t.Fatal("expected --expvar flag on sdk command")
 	}
+	if sdkCmd.Flag("cache") == nil {
+		t.Fatal("expected --cache flag on sdk command")
+	}
+	if sdkCmd.Flag("cache-ttl") == nil {
+		t.Fatal("expected --cache-ttl flag on sdk command")
+	}
+	if sdkCmd.Flag("cache-max-entries") == nil {
+		t.Fatal("expected --cache-max-entries flag on sdk command")
+	}
+	if sdkCmd.Flag("cache-max-bytes") == nil {
+		t.Fatal("expected --cache-max-bytes flag on sdk command")
+	}
+	if sdkCmd.Flag("i18n-default-locale") == nil {
+		t.Fatal("expected --i18n-default-locale flag on sdk command")
+	}
+	if sdkCmd.Flag("i18n-supported-locales") == nil {
+		t.Fatal("expected --i18n-supported-locales flag on sdk command")
+	}
 	if sdkCmd.Flag("terms-of-service") == nil {
 		t.Fatal("expected --terms-of-service flag on sdk command")
 	}
@@ -795,25 +886,31 @@ func TestAPISDKCmd_Good_TempSpecUsesMetadataFlags(t *testing.T) {
 	api.RegisterSpecGroups(specCmdStubGroup{})
 
 	builder, err := sdkSpecBuilder(specBuilderConfig{
-		title:             "Custom SDK API",
-		summary:           "Custom SDK overview",
-		description:       "Custom SDK description",
-		version:           "9.9.9",
-		swaggerPath:       "/docs",
-		graphqlPath:       "/gql",
-		graphqlPlayground: true,
-		ssePath:           "/events",
-		wsPath:            "/ws",
-		pprofEnabled:      true,
-		expvarEnabled:     true,
-		termsURL:          "https://example.com/terms",
-		contactName:       "SDK Support",
-		contactURL:        "https://example.com/support",
-		contactEmail:      "support@example.com",
-		licenseName:       "EUPL-1.2",
-		licenseURL:        "https://eupl.eu/1.2/en/",
-		servers:           "https://api.example.com, /, https://api.example.com",
-		securitySchemes:   `{"apiKeyAuth":{"type":"apiKey","in":"header","name":"X-API-Key"}}`,
+		title:                "Custom SDK API",
+		summary:              "Custom SDK overview",
+		description:          "Custom SDK description",
+		version:              "9.9.9",
+		swaggerPath:          "/docs",
+		graphqlPath:          "/gql",
+		graphqlPlayground:    true,
+		ssePath:              "/events",
+		wsPath:               "/ws",
+		pprofEnabled:         true,
+		expvarEnabled:        true,
+		cacheEnabled:         true,
+		cacheTTL:             "5m0s",
+		cacheMaxEntries:      42,
+		cacheMaxBytes:        8192,
+		i18nDefaultLocale:    "en-GB",
+		i18nSupportedLocales: "en-GB,fr,en-GB",
+		termsURL:             "https://example.com/terms",
+		contactName:          "SDK Support",
+		contactURL:           "https://example.com/support",
+		contactEmail:         "support@example.com",
+		licenseName:          "EUPL-1.2",
+		licenseURL:           "https://eupl.eu/1.2/en/",
+		servers:              "https://api.example.com, /, https://api.example.com",
+		securitySchemes:      `{"apiKeyAuth":{"type":"apiKey","in":"header","name":"X-API-Key"}}`,
 	})
 	if err != nil {
 		t.Fatalf("unexpected error building sdk spec: %v", err)
@@ -878,6 +975,29 @@ func TestAPISDKCmd_Good_TempSpecUsesMetadataFlags(t *testing.T) {
 		t.Fatal("expected expvar path to be included in generated spec")
 	}
 
+	if got := spec["x-cache-enabled"]; got != true {
+		t.Fatalf("expected x-cache-enabled=true, got %v", got)
+	}
+	if got := spec["x-cache-ttl"]; got != "5m0s" {
+		t.Fatalf("expected x-cache-ttl=5m0s, got %v", got)
+	}
+	if got := spec["x-cache-max-entries"]; got != float64(42) {
+		t.Fatalf("expected x-cache-max-entries=42, got %v", got)
+	}
+	if got := spec["x-cache-max-bytes"]; got != float64(8192) {
+		t.Fatalf("expected x-cache-max-bytes=8192, got %v", got)
+	}
+	if got := spec["x-i18n-default-locale"]; got != "en-GB" {
+		t.Fatalf("expected x-i18n-default-locale=en-GB, got %v", got)
+	}
+	locales, ok := spec["x-i18n-supported-locales"].([]any)
+	if !ok {
+		t.Fatalf("expected x-i18n-supported-locales array, got %T", spec["x-i18n-supported-locales"])
+	}
+	if len(locales) != 2 || locales[0] != "en-GB" || locales[1] != "fr" {
+		t.Fatalf("expected supported locales [en-GB fr], got %v", locales)
+	}
+
 	if info["termsOfService"] != "https://example.com/terms" {
 		t.Fatalf("expected termsOfService to be preserved, got %v", info["termsOfService"])
 	}
diff --git a/cmd/api/spec_builder.go b/cmd/api/spec_builder.go
index 0318894..6134543 100644
--- a/cmd/api/spec_builder.go
+++ b/cmd/api/spec_builder.go
@@ -2,7 +2,11 @@
 
 package api
 
-import goapi "dappco.re/go/core/api"
+import (
+	"strings"
+
+	goapi "dappco.re/go/core/api"
+)
 
 type specBuilderConfig struct {
 	title                   string
@@ -16,6 +20,12 @@ type specBuilderConfig struct {
 	wsPath                  string
 	pprofEnabled            bool
 	expvarEnabled           bool
+	cacheEnabled            bool
+	cacheTTL                string
+	cacheMaxEntries         int
+	cacheMaxBytes           int
+	i18nDefaultLocale       string
+	i18nSupportedLocales    string
 	termsURL                string
 	contactName             string
 	contactURL              string
@@ -41,6 +51,11 @@ func newSpecBuilder(cfg specBuilderConfig) (*goapi.SpecBuilder, error) {
 		WSPath:                  cfg.wsPath,
 		PprofEnabled:            cfg.pprofEnabled,
 		ExpvarEnabled:           cfg.expvarEnabled,
+		CacheEnabled:            cfg.cacheEnabled || strings.TrimSpace(cfg.cacheTTL) != "" || cfg.cacheMaxEntries > 0 || cfg.cacheMaxBytes > 0,
+		CacheTTL:                strings.TrimSpace(cfg.cacheTTL),
+		CacheMaxEntries:         cfg.cacheMaxEntries,
+		CacheMaxBytes:           cfg.cacheMaxBytes,
+		I18nDefaultLocale:       strings.TrimSpace(cfg.i18nDefaultLocale),
 		TermsOfService:          cfg.termsURL,
 		ContactName:             cfg.contactName,
 		ContactURL:              cfg.contactURL,
@@ -52,6 +67,11 @@ func newSpecBuilder(cfg specBuilderConfig) (*goapi.SpecBuilder, error) {
 		ExternalDocsURL:         cfg.externalDocsURL,
 	}
 
+	builder.I18nSupportedLocales = parseLocales(cfg.i18nSupportedLocales)
+	if builder.I18nDefaultLocale == "" && len(builder.I18nSupportedLocales) > 0 {
+		builder.I18nDefaultLocale = "en"
+	}
+
 	if cfg.securitySchemes != "" {
 		schemes, err := parseSecuritySchemes(cfg.securitySchemes)
 		if err != nil {
@@ -62,3 +82,7 @@ func newSpecBuilder(cfg specBuilderConfig) (*goapi.SpecBuilder, error) {
 
 	return builder, nil
 }
+
+func parseLocales(raw string) []string {
+	return splitUniqueCSV(raw)
+}